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Department of Human Nutrition, Foods, and Exercise (J.W.R., L.P.G., M.J.P., S.M.N.-R., C.P.E.), Virginia Tech, Blacksburg, Virginia
Department of Dairy Sciences (F.C.G.), Virginia Tech, Blacksburg, Virginia
Address reprint requests to: Janet Walberg Rankin, Ph.D., Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg VA 24061-0430. E-mail: jrankin{at}vt.edu
Objective: Athletes are interested in nutritional manipulations that may enhance lean tissue gains stimulated by resistance training. Some research demonstrates that acute consumption of food containing protein causes superior muscle protein synthesis compared to isoenergetic foods without protein. This benefit has not been verified in longer-term training studies. We compared body composition and muscle function responses to resistance training in males who consumed a carbohydrate or a multi-macronutrient beverage following each training session.
Methods: Nineteen, untrained men (1825 years) consumed either a milk (MILK) or a carbohydrate-electrolyte (CHO) drink immediately following each workout during a 10 week resistance training program. Muscle strength (1RM for seven exercises), body composition (DXA scan), fasted, resting concentrations of serum total and free testosterone, cortisol, IGF-1, and resting energy expenditure (REE) were measured prior to and at the end of training.
Results: Resistance training caused an increase (44 ± 4%, p < 0.001) in muscular strength for all subjects. The training program reduced percent body fat (8%, p < 0.05, 0.9 ± 0.5 kg) and increased fat-free soft tissue (FFST) mass (2%, 1.2 ± 0.3 kg, p < 0.01). MILK tended to increase body weight and FFST mass (p=0.10 and p=0.13, respectively) compared to CHO. Resting total and free testosterone concentrations decreased from baseline values in all subjects (16.7%, 11%, respectively, p < 0.05). Significant changes in fasting IGF-1, cortisol, and REE across training were not observed for either group.
Conclusion: Post-resistance exercise consumption of MILK and CHO caused similar adaptations to resistance training. It is possible that a more prolonged training with supplementation period would expand the trend for greater FFST gains in MILK.
Key words: body composition, nutrition for strength athletes, weight training, testosterone, hypertrophy
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